Companion planting is one of the best ways to boost your garden’s productivity. Most plants do very well with companions, and some plants will grow even better with companions than when they’re alone. This is a technique that farmers have been practicing for thousands of years, and if you look around, you can see it happening naturally. Certain plants are usually found growing beside each other and providing mutual benefits that they all enjoy.
However, it isn’t magic, and not all plants will grow well beside each other. There are ways to go about it, so before you go ahead and start planting everything beside everything else, read the rest of this article. If done well, companion planting can produce surprising results.
What Is Companion Planting?
To put it simply, companion planting means growing plants side by side such that they mutually benefit each other. Just like humans, plants can benefit from companions, plants can also grow better when near other plants that compliment them. One plant can help the other repel insects and pests, while the other supplies additional nutrients to the soil, which is available to its companion, or help to lower disease risks.
The idea behind it is straightforward but very effective when done well. Plants rarely grow in isolation in nature. They are usually around other species, and they tend to grow very well in these situations. Mimicking this natural environment can yield outstanding results in your garden or farm. Companion planting is just another step you can take to help create the ideal environment for your plant that mimics how it would grow in nature.
A prevalent example of this is the combination known as the “Three Sisters,” which is very common in Native American farming societies. This is a combination of pole beans, corn, and squash, and they thrive when they’re together. The corn stalks provide support for the beans, which pull nitrogen into the soil from the air for all three of them. The squash has large leaves, which provide shade for the soil, and this keeps it cool and moist and stops weeds from growing. The squash also has spiky stems and leaves that help to deter pests. It’s a great combination, and it benefits all the plants—the perfect example of companion planting.
This is just one such example, there are dozens more. Nearly every plant can benefit from the correct companion. We’ll look more later on specific plants and what goes well with them, as well as which plants you should avoid.
What Are the Benefits of Companion Planting?
Companion planting provides numerous benefits, here are just a few of them.
It Saves Space
Companion planting helps save space in your garden because planting your crops together will take up less space. You can combine plants with deep roots with those with shallow roots to take full advantage of this. This helps you maximize your space, and grow more crops with less room.
Instead of using chemical pesticides, you can use plants that act as natural deterrents to those pests. Certain plants are shown to deter pests from visiting your garden, so depending on which companions work with your plants they may be able to keep pests away.
Some plants can act as physical support, like the corn in the “Three Sisters” example, but they also provide support in other ways. This can be providing essential nutrients, repelling pests, and even helping to prevent disease.
In addition to having more space to plant and fewer pests, you’ll also have increased productivity because the plants help each other grow and benefit each other. It helps to support the needs of your plants, and this will increase their productivity and ability to produce flowers or edible crops.
Planting sprawling crops around taller ones will reduce the open space around them. This is where weeds would normally thrive, so this suppresses them.
Protection and Shade Regulation
Larger plants can provide much-needed shade for smaller plants that need protection from the sun. They can also provide a measure of protection from the elements such as rain and wind.
Attracting Beneficial Insects
Beneficial insects are insects that provide advantages, such as bees which are popularly known for their pollinating ability. However, companion plants can also attract insects that feed on smaller insect pests of the other plants, allowing for healthier growth.
Does Companion Planting Work Indoors?
Absolutely! Companion planting works indoors just as well as outdoors. However, there are a few rules to follow if you want multiple houseplants to grow well together in a container.
First and most important, they should have similar growing conditions. That way, they can grow well together, and you won’t have one struggling to survive. If one plant needs to be watered everyday but the other only once per week you’re going to struggle to keep them both healthy.
You should also make sure there is some space between your plants because having them too close can cause them to compete for resources when those resources are limited. This also means that you should make sure that your chosen container is large enough to support both plants. While this is usually smaller than if you grow both separately, it is likely a little larger than the container needed for each plant individually.
Most plants will grow well as companions, but mint is a prime example of a harmful companion plant. It will try to take over any space provided and compete with other plants for available resources. Also, some plants like the Cherry Laurel are allelopathic, producing chemicals that may affect the survival of other organisms and make the soil around them toxic. It would be best to make sure the plants you want to combine can serve as good companions.
Outside of that, indoor companion plant growing is very similar to outdoors. Follow the same tips and techniques, and you’ll be able to successfully grow multiple plants in unison.
What Makes a Bad Companion?
As we’ve alluded to, not all plants are good for companion growing. When deciding which plants to grow, keep the following ideas in mind and consider a different plant if any of them are true.
Plants with Incompatible Growth Conditions
When two plants require very different conditions to grow, they’re not going to grow well together. An excellent example of this is the combination of succulents and ferns. Both types of plants are native to very different environments. They both have different water and sunlight requirements, among others. Still, the most significant issue between them is that ferns constantly require moist soil to grow but maintaining that moisture level will cause the roots of any succulent plant to rot.
It’s best to avoid planting plants that differ like this too close together. Otherwise, it becomes very difficult to provide the proper care to each.
Allelopathic plants release toxic chemicals into their immediate environment, which affects the growth, reproduction, productivity, and survival of other plants. Although not much research has been done examining and detailing the mechanism and cause of allelopathy in plants, it is believed that some plants do this in an attempt to protect themselves.
Examples of allelopathic plants are asparagus, sunflowers, tomatoes, peas, cabbage, and cucumbers. Some plants only affect certain other plants. Examples are strawberries which affect all members of the cabbage (brassica) family, cucumbers which can cause potato blight in late potatoes, and potatoes can also disturb some sensitive pumpkin roots.
When growing close to each other, plants will compete for resources to survive. Plants that compete aggressively with others will make very bad companions. An excellent example of this is the mint mentioned above, and other examples are artemisia, catnip, horseradish, spearmint, lemon balm, English ivy, chickweed, and garlic mustard. When practicing companion planting, it is important to understand the resources each plant needs and ensure that competition, if any, is healthy and to know the list of plants you can grow together.
With some of the science behind companion planting out of the way, let’s look at some specific recommendations for companion planting. Each of the sections below will look at a few popular plants, and then list a few good companions for them.
- Strawberries: Chives, lettuce, bush beans, spinach, squash, onions, caraway, and sage.
- Cabbage: Celery, spinach, chard, onions, lettuce, and beets.
- Corn: Cucumber, climbing beans, peas, zucchini, squash, and sunflowers.
- Beans: Carrots, chard, radishes, cucumbers, beets, corn, peas, and cabbages.
- Asparagus: Carrots, dill, basil, tomatoes, cilantro, parsley, and marigold.
- Beets: Broccoli, cabbage, bush beans, cauliflower, chard, onions, kohlrabi, and brussels sprouts.
- Potatoes: Basil, marigolds, peas, onions, spinach, garlic, beans, horseradish, corn, lettuce, radishes, and celery.
- Squash: Dill, corn, sunflowers, peas, marigolds, strawberries, nasturtiums, radishes, and beans.
- Pumpkin: Corn, squash, nasturtiums, beans, and marigolds.
- Broccoli: Chamomile, garlic, dill, mint, nasturtiums, onions, spinach, sage, beets, rosemary, bush beans, basil, lettuce, radishes, cucumber, thyme, celery, and carrots.
- Zucchini: Beans, spinach, nasturtiums, peas, radishes, dill, corn, marigolds, and garlic.
- Basil: Peppers, eggplant, marigolds, oregano, parsley, cabbage, beans, tomatoes, beets, and asparagus.
- Rosemary: Broccoli, cauliflower, garlic, peppers, cabbage, carrots, beans, and sage.
- Catnip: Hyssop, beets, squash, and pumpkin.
- Chives: Dill, tomatoes, tarragon, marjoram, and carrots.
- Sage: Rosemary.
- Bay: Rosemary, parsley, thyme, and sage.
- Cilantro: Anise, dill, spinach, and caraway.
- Oregano: Peppers, beans, squash, cauliflower, turnips, kohlrabi, eggplant, brussels sprouts, and broccoli.
- Marjoram: Chives, rosemary, oregano, sage, thyme, lavender, basil, and parsley.
- Dill: Onions, cucumbers, cabbages, eggplants, lettuce, and corn.
- Lavender: Leeks, aster, and carrots.
- Hibiscus: Daylilies, poppies, alyssum, and peonies.
- Daylilies: Achillea, salvia, lavender, yarrow, and black-eyed Susan.
- Marigold: Cabbage, kale, eggplant, squash, cucumber, basil, broccoli, and tomatoes.
- Sunflower: Lettuce, squash, onion, corn, peppers, cucumber, and nasturtiums.
- Roses: Sage, chives, garlic, lavender, thyme, allium, and rosemary.
Tips For Planning a Companion Garden
If you’ve decided to start companion growing, and we highly recommend you do, here’s some additional information to help you plan and cultivate the perfect garden.
Combine Plants That Prefer Similar Environments
Well, this should be obvious, but it bears repeating. Plants that grow well under the same conditions will grow well together. However, if they’re bad companions and have properties that will impede each other’s growth, you should keep them apart, even if they have similar growing conditions. Good companions don’t just share similar environmental needs, but also don’t hamper each other’s growth.
Combine Fast and Slow Growing Plants to Maximize Your Space
This is a surprisingly effective method of conserving space. For example, radishes mature quickly, so you can plant them with squash because, by the time you’re harvesting the radishes, the squash would just have become big enough to take over that space.
They can also mark rows of the other slow-growing seeds you plant. Radishes, again, serve very well here because they’ll spring up a few days after you grow them. If you sprinkle some radish seeds along with the other seeds you want to plant they’ll help you mark out the rows you’ve planted and likely mature and be harvested before the other plants.
To Help Future Crops, You Can Use Plants to Improve the Soil
Some plants have unique properties that help to improve the soil after they have been harvested making it easier for other plants that take their place to grow. An example of this are plants called “dynamic accumulators.” These plants have deep roots that pull minerals from deep areas within the soil through phytoaccumulation.
When their leaves fall, or they die and decompose, they deposit these minerals back into the soil, and these become available for the shallow-rooted plants around or the ones that take their place. Some examples of these plants are amaranth, moringa, yarrow, dandelions, borage, maple and apple trees, chicory, and mulberry.
Separate Plants That Are Susceptible to Similar Diseases Or Pests
Having plants prone to the same diseases together helps those diseases spread faster and cause more destruction if any of your plants get infected. Plants like tomatoes and potatoes should be separated because the blight affects both and can quickly spread from one to the other.
The reverse is also true, plants that are susceptible to different diseases can help slow the spread. This limits the disease or pests ability to spread, and can help contain issues to small parts of your garden.
Attracting Pollinators Through Companion Planting
Flowers do more than beautify your garden. Having an extensive collection of diverse flower species is an excellent way to attract pollinators. Pollinators are important as many plants won’t properly bloom without them. Here are some ways to do this:
For herbs, basil attracts swarms of bees if left to blossom. Some other pollinators attracting herbs include dill, sage, thyme, and oregano blossom in your garden. Allowing any of these to bloom is likely to bring bees and other beneficial insects into your garden.
Some more combinations that can help are sweet peas and runner beans, borage and strawberry, basil and oregano, summer squash and calendula, sunflowers, cucumbers and marigolds with plants like onions, tomatoes, melons, lettuce, cucumbers, and squash. These are all great companion choices and sure to attract pollinators.
Some other flowering plants that can be great companions are bee balm, alyssum, rosemary, and nasturtiums. Most flowering plants will attract pollinators, so it’s hard to go wrong.
What’s nice about attracting pollinators is that you usually don’t have to practice strict companion gardening to see the benefit. For example, flowers nearby, but not close enough to be a companion, are still likely to bring in beneficial insects.
Repelling Garden Pests Through Companion Planting
This is beneficial information for any gardener, especially those who don’t want to rely on chemical-based pesticides. We can go back to the Three Sisters for an example of this; the spiky stems and squash leaves that deter pests. Here are some examples of plants that can act as companions and help with the pests:
- Ants: Lavender, thyme, marigolds, garlic, rosemary, and tansy.
- Aphids: Rosemary, dill, cilantro, oregano, basil, thyme, lavender, catnip, and chives.
- Asparagus beetle: Basil, marigolds, and parsley.
- Bean beetle: Summer savory, nasturtium, marigolds, and rosemary.
- Cabbage moth: Tansy, thyme, marigolds, oregano, sage, hyssop, southernwood, and tomatoes.
- Carrot fly: Chives, rosemary, onions, sage, and leeks.
- Flea beetle: Dill and marigolds.
- Fruit tree moths: Nasturtiums, sage, and southernwood.
- Japanese beetles: Rue, catnip, garlic, tansy, chives, white geranium, marigolds, and nasturtium.
- Mosquitoes: Garlic, rosemary, and basil.
- Moths: Santolina.
- Nematodes: Marigolds and dahlia.
- Potato bugs: Cilantro, nasturtium, horseradish, and tansy.
- Squash bugs and beetles: Marigolds, tansy, catnip, radishes, and nasturtiums.
- Ticks: Rosemary, garlic, rue, marigolds, and lavender.
Mint also helps to deter many pests, but you should be careful with it; if not, it’ll end up competing with your plants.
While these aren’t perfect pest control techniques, they are still quite effective at controlling pests. If you know your garden is prone to a certain type of pest, growing plants that deter it can help reduce maintenance needed during the growing season.
Are you thinking about improving the productivity of your indoor garden? One way to do it organically is companion planting. If you’ve read this article, you now understand how companion planting works, the benefits and which plants you can grow together for maximum benefit. When done right, companion planting will help your garden thrive, and you’ll be surprised how much you can gain without excessive use of nutrients or pesticides.
Companion Gardening FAQ
How Close Is Too Close For Companion Planting?
It largely depends on the variety of plants, you still want to make sure that each plant has enough space to grow and obtain nutrients. A good rule of thumb is to take the average spacing for each plant. If one plant has 12” of spacing while the other needs 6”, then planting them about 9” apart is a good place to start.
Do Plants Grow Better With Other Plants Around Them?
In many cases yes. Not every plant is suitable for companion planting, but those that are can be extremely beneficial to nearby plants.
What Are Bad Companions For Tomatoes?
Cabbage and corn are bad companions for tomatoes and will stunt its growth. On the flip side, chives and asparagus are great companions for your tomato plant.
Do All Plants Have Companions?
Most do, but some are more picky than others on which plants are grown near them. Certain plants, like mint, generally are not good companion growers due to their tendency to steal too many nutrients from surrounding plants.
Does Companion Growing Work Indoors or In a Greenhouse?
Yes! Companion growing can work regardless of where your plants are grown. You should ensure that when growing multiple plants in the same container that you provide enough space for them both to grow.